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davidtwcodavidtwco
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resolve: prohibit foreign statics w/ generics
This commit modifies resolve to disallow foreign statics that use parent generics. `improper_ctypes` is not written to support type parameters, as these are normally disallowed before the lint is run. Thus, type parameters in foreign statics must be prohibited before the lint. The only other case where this *could* have occured is in functions, but typeck prohibits this with a "foreign items may not have type parameters" error - a similar error did not exist for statics, because statics cannot have type parameters, but they can use any type parameters that are in scope (which isn't the case for functions). Signed-off-by: David Wood <david@davidtw.co>
1 parent 7870050 commit ccbf2b7

8 files changed

+266
-181
lines changed

‎src/librustc_resolve/diagnostics.rs‎

Lines changed: 20 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,7 @@ use syntax_pos::{BytePos, Span, MultiSpan};
2020

2121
use crate::resolve_imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver};
2222
use crate::{path_names_to_string, KNOWN_TOOLS};
23-
use crate::{BindingError, CrateLint, LegacyScope, Module, ModuleOrUniformRoot};
23+
use crate::{BindingError, CrateLint, HasGenericParams, LegacyScope, Module, ModuleOrUniformRoot};
2424
use crate::{PathResult, ParentScope, ResolutionError, Resolver, Scope, ScopeSet, Segment};
2525

2626
type Res = def::Res<ast::NodeId>;
@@ -102,7 +102,7 @@ impl<'a> Resolver<'a> {
102102
&self, span: Span, resolution_error: ResolutionError<'_>
103103
) -> DiagnosticBuilder<'_> {
104104
match resolution_error {
105-
ResolutionError::GenericParamsFromOuterFunction(outer_res) => {
105+
ResolutionError::GenericParamsFromOuterFunction(outer_res, has_generic_params) => {
106106
let mut err = struct_span_err!(self.session,
107107
span,
108108
E0401,
@@ -148,22 +148,24 @@ impl<'a> Resolver<'a> {
148148
}
149149
}
150150

151-
// Try to retrieve the span of the function signature and generate a new message
152-
// with a local type or const parameter.
153-
let sugg_msg = &format!("try using a local generic parameter instead");
154-
if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
155-
// Suggest the modification to the user
156-
err.span_suggestion(
157-
sugg_span,
158-
sugg_msg,
159-
new_snippet,
160-
Applicability::MachineApplicable,
161-
);
162-
} else if let Some(sp) = cm.generate_fn_name_span(span) {
163-
err.span_label(sp,
164-
format!("try adding a local generic parameter in this method instead"));
165-
} else {
166-
err.help(&format!("try using a local generic parameter instead"));
151+
if has_generic_params == HasGenericParams::Yes {
152+
// Try to retrieve the span of the function signature and generate a new
153+
// message with a local type or const parameter.
154+
let sugg_msg = &format!("try using a local generic parameter instead");
155+
if let Some((sugg_span, snippet)) = cm.generate_local_type_param_snippet(span) {
156+
// Suggest the modification to the user
157+
err.span_suggestion(
158+
sugg_span,
159+
sugg_msg,
160+
snippet,
161+
Applicability::MachineApplicable,
162+
);
163+
} else if let Some(sp) = cm.generate_fn_name_span(span) {
164+
err.span_label(sp,
165+
format!("try adding a local generic parameter in this method instead"));
166+
} else {
167+
err.help(&format!("try using a local generic parameter instead"));
168+
}
167169
}
168170

169171
err

‎src/librustc_resolve/late.rs‎

Lines changed: 116 additions & 139 deletions
Large diffs are not rendered by default.

‎src/librustc_resolve/lib.rs‎

Lines changed: 25 additions & 21 deletions
Original file line numberDiff line numberDiff line change
@@ -61,7 +61,7 @@ use rustc_data_structures::sync::Lrc;
6161

6262
use diagnostics::{Suggestion, ImportSuggestion};
6363
use diagnostics::{find_span_of_binding_until_next_binding, extend_span_to_previous_binding};
64-
use late::{PathSource, Rib, RibKind::*};
64+
use late::{HasGenericParams, PathSource, Rib, RibKind::*};
6565
use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
6666
use macros::{LegacyBinding, LegacyScope};
6767

@@ -178,7 +178,7 @@ impl Ord for BindingError {
178178

179179
enum ResolutionError<'a> {
180180
/// Error E0401: can't use type or const parameters from outer function.
181-
GenericParamsFromOuterFunction(Res),
181+
GenericParamsFromOuterFunction(Res, HasGenericParams),
182182
/// Error E0403: the name is already used for a type or const parameter in this generic
183183
/// parameter list.
184184
NameAlreadyUsedInParameterList(Name, Span),
@@ -2167,7 +2167,7 @@ impl<'a> Resolver<'a> {
21672167
ForwardTyParamBanRibKind | TyParamAsConstParamTy => {
21682168
// Nothing to do. Continue.
21692169
}
2170-
ItemRibKind | FnItemRibKind | AssocItemRibKind => {
2170+
ItemRibKind(_) | FnItemRibKind | AssocItemRibKind => {
21712171
// This was an attempt to access an upvar inside a
21722172
// named function item. This is not allowed, so we
21732173
// report an error.
@@ -2195,22 +2195,23 @@ impl<'a> Resolver<'a> {
21952195
}
21962196
Res::Def(DefKind::TyParam, _) | Res::SelfTy(..) => {
21972197
for rib in ribs {
2198-
match rib.kind {
2198+
let has_generic_params = match rib.kind {
21992199
NormalRibKind | AssocItemRibKind |
22002200
ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
22012201
ConstantItemRibKind | TyParamAsConstParamTy => {
22022202
// Nothing to do. Continue.
2203+
continue;
22032204
}
2204-
ItemRibKind | FnItemRibKind => {
2205-
// This was an attempt to use a type parameter outside its scope.
2206-
if record_used {
2207-
self.report_error(
2208-
span, ResolutionError::GenericParamsFromOuterFunction(res)
2209-
);
2210-
}
2211-
return Res::Err;
2212-
}
2205+
// This was an attempt to use a type parameter outside its scope.
2206+
ItemRibKind(has_generic_params) => has_generic_params,
2207+
FnItemRibKind => HasGenericParams::Yes,
2208+
};
2209+
2210+
if record_used {
2211+
self.report_error(span, ResolutionError::GenericParamsFromOuterFunction(
2212+
res, has_generic_params));
22132213
}
2214+
return Res::Err;
22142215
}
22152216
}
22162217
Res::Def(DefKind::ConstParam, _) => {
@@ -2222,15 +2223,18 @@ impl<'a> Resolver<'a> {
22222223
ribs.next();
22232224
}
22242225
for rib in ribs {
2225-
if let ItemRibKind | FnItemRibKind = rib.kind {
2226-
// This was an attempt to use a const parameter outside its scope.
2227-
if record_used {
2228-
self.report_error(
2229-
span, ResolutionError::GenericParamsFromOuterFunction(res)
2230-
);
2231-
}
2232-
return Res::Err;
2226+
let has_generic_params = match rib.kind {
2227+
ItemRibKind(has_generic_params) => has_generic_params,
2228+
FnItemRibKind => HasGenericParams::Yes,
2229+
_ => continue,
2230+
};
2231+
2232+
// This was an attempt to use a const parameter outside its scope.
2233+
if record_used {
2234+
self.report_error(span, ResolutionError::GenericParamsFromOuterFunction(
2235+
res, has_generic_params));
22332236
}
2237+
return Res::Err;
22342238
}
22352239
}
22362240
_ => {}

‎src/test/ui/inner-static-type-parameter.stderr‎

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -2,9 +2,7 @@ error[E0401]: can't use generic parameters from outer function
22
--> $DIR/inner-static-type-parameter.rs:6:19
33
|
44
LL | fn foo<T>() {
5-
| --- - type parameter from outer function
6-
| |
7-
| try adding a local generic parameter in this method instead
5+
| - type parameter from outer function
86
LL | static a: Bar<T> = Bar::What;
97
| ^ use of generic parameter from outer function
108

‎src/test/ui/resolve/issue-65025-extern-static-parent-generics.rs‎

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
1+
unsafe fn foo<A>() {
2+
extern "C" {
3+
static baz: *const A;
4+
//~^ ERROR can't use generic parameters from outer function
5+
}
6+
7+
let bar: *const u64 = core::mem::transmute(&baz);
8+
}
9+
10+
fn main() { }

‎src/test/ui/resolve/issue-65025-extern-static-parent-generics.stderr‎

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
1+
error[E0401]: can't use generic parameters from outer function
2+
--> $DIR/issue-65025-extern-static-parent-generics.rs:3:28
3+
|
4+
LL | unsafe fn foo<A>() {
5+
| - type parameter from outer function
6+
LL | extern "C" {
7+
LL | static baz: *const A;
8+
| ^ use of generic parameter from outer function
9+
10+
error: aborting due to previous error
11+
12+
For more information about this error, try `rustc --explain E0401`.

‎src/test/ui/resolve/issue-65035-static-with-parent-generics.rs‎

Lines changed: 29 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,29 @@
1+
#![feature(const_generics)]
2+
//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
3+
4+
fn f<T>() {
5+
extern "C" {
6+
static a: *const T;
7+
//~^ ERROR can't use generic parameters from outer function
8+
}
9+
}
10+
11+
fn g<T: Default>() {
12+
static a: *const T = Default::default();
13+
//~^ ERROR can't use generic parameters from outer function
14+
}
15+
16+
fn h<const N: usize>() {
17+
extern "C" {
18+
static a: [u8; N];
19+
//~^ ERROR can't use generic parameters from outer function
20+
}
21+
}
22+
23+
fn i<const N: usize>() {
24+
static a: [u8; N] = [0; N];
25+
//~^ ERROR can't use generic parameters from outer function
26+
//~^^ ERROR can't use generic parameters from outer function
27+
}
28+
29+
fn main() {}

‎src/test/ui/resolve/issue-65035-static-with-parent-generics.stderr‎

Lines changed: 53 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,53 @@
1+
error[E0401]: can't use generic parameters from outer function
2+
--> $DIR/issue-65035-static-with-parent-generics.rs:6:26
3+
|
4+
LL | fn f<T>() {
5+
| - type parameter from outer function
6+
LL | extern "C" {
7+
LL | static a: *const T;
8+
| ^ use of generic parameter from outer function
9+
10+
error[E0401]: can't use generic parameters from outer function
11+
--> $DIR/issue-65035-static-with-parent-generics.rs:12:22
12+
|
13+
LL | fn g<T: Default>() {
14+
| - type parameter from outer function
15+
LL | static a: *const T = Default::default();
16+
| ^ use of generic parameter from outer function
17+
18+
error[E0401]: can't use generic parameters from outer function
19+
--> $DIR/issue-65035-static-with-parent-generics.rs:18:24
20+
|
21+
LL | fn h<const N: usize>() {
22+
| - const parameter from outer function
23+
LL | extern "C" {
24+
LL | static a: [u8; N];
25+
| ^ use of generic parameter from outer function
26+
27+
error[E0401]: can't use generic parameters from outer function
28+
--> $DIR/issue-65035-static-with-parent-generics.rs:24:20
29+
|
30+
LL | fn i<const N: usize>() {
31+
| - const parameter from outer function
32+
LL | static a: [u8; N] = [0; N];
33+
| ^ use of generic parameter from outer function
34+
35+
error[E0401]: can't use generic parameters from outer function
36+
--> $DIR/issue-65035-static-with-parent-generics.rs:24:29
37+
|
38+
LL | fn i<const N: usize>() {
39+
| - const parameter from outer function
40+
LL | static a: [u8; N] = [0; N];
41+
| ^ use of generic parameter from outer function
42+
43+
warning: the feature `const_generics` is incomplete and may cause the compiler to crash
44+
--> $DIR/issue-65035-static-with-parent-generics.rs:1:12
45+
|
46+
LL | #![feature(const_generics)]
47+
| ^^^^^^^^^^^^^^
48+
|
49+
= note: `#[warn(incomplete_features)]` on by default
50+
51+
error: aborting due to 5 previous errors
52+
53+
For more information about this error, try `rustc --explain E0401`.

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